Halide　solid　electrolytes　receive　much　attention　due　to　their　electrochemical　properties,　such　as　high　ionic　conductivity,　oxidative　stability,　and　ease　of　preparation.　In　this　work,　a　bromide　solid　electrolyte　LiBiBr4,　exhibiting　ease　of　processing　and　high　ionic　conductivity,　is　designed　for　the　first　time　and　investigated　through　a　comparative　investigation　with　monoclinic　LiAlCl4　and　LiAlBr4　for　the　migration　path.　The　processing　pressure　for　LiBiBr4　with　annealing　at　120 °C　is　less　than　one-tenth　that　of　other　chloride　electrolytes　(≈5 MPa).　Computational　analyses　unveil　crucial　mechanistic　insights　into　the　three　migration　mechanisms　and　the　factors　that　influence　them　within　the　monoclinic　structure.　The　distribution　and　distance　of　non-Li　polyhedrons　to　the　migration　pathways　are　pivotal　for　the　migration.　The　strategic　positioning　of　the　Bi　polyhedron　in　LiBiBr4　is　far　from　the　Li+　pathway.　The　unique　leap　migration　within　the　LiBiBr4　has　a　lower　energy　barrier　and　facilitates　an　interconnected　migration　that　forms　a　3D　interstice　network.　This　interconnected　leap　migration　network　within　LiBiBr4　constitutes　a　Z-type　interstice　leap　migration　along　the　ab-axis.　Thus,　the　LiBiBr4　obtains　a　high　ionic　conductivity　of　0.19　mS　cm−1　with　the　0.349 eV　low　activation　energy.　This　discovery　and　research　methods　provide　significant　impetus　and　support　for　the　development　of　halogen-based　electrolytes.　©　2025　Wiley-VCH　GmbH.